such as trichloroacetic acid (TCA) are also performed in the doctor’s office or in an ambulatory surgery center as an outpatient procedure and can cause more discomfort. Frequently, the combination of a tranquilizer such as diazepam and an oral analgesic is administered. TCA peels often do not require anesthesia even if the solution itself has - at the contrary of phenol - no numbing effect on the skin. The patient usually feels a warm or burning sensation. Phenol used to be a deep chemical peel. Early phenol peel solutions were very painful and most practitioners would perform it under either general anesthesia, administered by an anesthesiologist or nurse anesthetist. Today it is more correctly referred to as a croton oil peel, since that has proven to be the active ingredient responsible for most of its effects. Recent formulations allow more variation in the depth of treatment, and allow its use under sedation either orally or intravenously, usually in conjunction with local anesthetic injections. See also List of cutaneous conditions References Skin care